This invention relates to the recovery of machine tool cutting or cooling liquids, and more particularly to apparatus of the type which utilizes chip wringers for separating cooling or cutting liquids from the waste produced by lathes, milling machines, drills, and the like. Even more particularly this invention relates an improved chute feeding device for supplying a mixture of cooling or cutting liquid and chips, turnings, bar ends, tramp metal and the like to a chip wringer for separation thereby.
Because of both the economies of operation and environmental considerations, it has long been customary to retrieve cooling and/or cutting liquids and lubricants which are directed onto the cutting tools of machine tools, such as lathes, milling machines, drills, and the like during a cutting operation. The plastic and/or metal turnings, chips, bar ends and tramp metal produced during such an operation are conveyed along with the cooling and/or cutting liquid to known apparatus of the type which separates the liquid from the solid waste, so that the liquid can be reused or disposed of without causing environmental contamination. Typically such separation occurs in a device known as a chip wringer, wherein mixtures of the liquid (cooling fluids) and solid waste (chips, turnings, etc.) are subjected to centrifugal forces that separate the liquid from the solid waste. Conventional chip wringers are disclosed, by way of example, in U.S. Pat. Nos. 3,233,735, 3,366,318, and 3,850,814.
As noted above, the waste or by-products produced by tools of the type described include not only small chips and turnings, but also rather large or heavy bar ends and tramp pieces of plastic or metal, which along with the chips, turnings and cooling fluids are delivered to the separating apparatus. However, because of the nature of the operation of chip wringers of the type described, it has been found most desirable to separate out the heavy or larger ends and tramp pieces from the waste before the latter is fed into the chip wringer. This preliminary separation is most important when the chip wringer comprises a rotating separator bowl or centrifuge of the type having radially inwardly projecting fins or baffles that strike the incoming waste products as they are fed into the rotating bowl. If the heavier pieces in the waste are allowed to enter the bowl they may jam or damage the bowl or its related equipment; and if they happen to pass through the wringer, they can cause problems downstream thereof, for example by plugging pneumatic conveying systems or the like.
One such means for effecting preliminary separation of the heavier parts from machine tool waste is disclosed in U.S. Pat. No. 4,310,417. With this apparatus waste products from machine tools are fed down an inclined feed chute into the bowl-shaped separator of a conventional chip wringer. The rotating separator bowl generates at the lower end of the chute a vacuum, which is utilized to draw the fluids and lighter metal chips down the chute into the wringer. An opening located in the bottom of the chute above its lower end permits the heavier waste materials (large end pieces and the like) to drop by gravity downwardly through the opening and out of the chute before reaching its lower end, so that the heavier pieces are not fed into the separator bowl of the wringer. Air rushing into the chute through the opening entrains the lighter waste materials (chips, etc.) and fluids and carries them over the opening so that they continue to pass downwardly out of the lower end of the chute and into the separator bowl.
One of the primary disadvantages of this conventional feed chute is that it is necessary to maintain a vacuum or suction in the chute throughout its length, and specifically at the opening through which the larger pieces drop. In other words, it is essential that the vacuum created by the wringer's rotating separator bowl be great enough to carry the lighter waste materials (chips, etc.) and cooling fluids or liquids over the opening in the bottom of the chute through which the heavier materials or bar ends drop. For this reason, such chute opening must be small enough to cause the entering air to reach a velocity great enough to overcome the gravitational forces which otherwise would cause the liquid and lighter waste particles (chips,turnings, etc.) also to drop out of the opening in the chute with the heavier materials. Since there is a limit to the vacuum which can be created by the rotating separator bowl, it is very critical that the entire feed chute be carefully sealed, except for the above-noted opening in the bottom thereof. Otherwise, it would be impossible to draw through the opening air in a quantity sufficient to entrain and cause the liquids or fluids and small chips to pass over the opening, and downwardly in the chute to the wringer.
This necessity for carefully selecting the size of the opening in the bottom of the chute also causes ancillary problems. For example, because the opening in question must be limited in size, it has been found that in many instances particularly long pieces of incoming waste materials tend to pass over the opening and slide downwardly in the chute to the wringer, where they often cause excessive damage to the wringer or to downstream equipment. This problem is particularly acute when the waste contains a finished part or tramp piece which accidentally may have become entrained in masses of wire or metal scrap turnings, and which therefore tends to pass over the opening in the bottom of the chute along with the cooling liquid and smaller chips.
It is an object of this invention, therefore, to provide for chip wringers of the type described an improved chute feed mechanism which is substantially more efficient than prior such mechanisms, and which obviates the need for maintaining a vacuum throughout the length of the associated chute.
Still another object of the invention is to provide for chip wringers and the like an improved, inclined feed chute which is designed to utilize both gravity and a stream of air for blowing lighter waste products and fluids transversely out of an opening which is located in the feed chute intermediate its ends.
A further object of this invention is to provide an improved, inverted, generally Y-shaped feed chute of the type described, which has adjustable vent means for controlling a stream of air used to assist in separating lighter particles and fluids from falling machine tool waste materials.
Another object of this invention is to provide an improved feed chute of the type described, which has an adjustable bypass mechanism for selectively interrupting the flow of lighter waste materials and fluids out of the chute to the associated chip wringer, thereby discharging all of the incoming waste material, out of the lower end of the chute.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with accompanying drawings.